Device and method for extraction of dust from a grinder

ABSTRACT

A plug for a grinding machine includes one or more holes extending through to the plug for use as dust collection ports. A grinding machine includes a housing, a drive mechanism including a shaft extending through the housing, a shroud surrounding the shaft and abutting the housing to form a plenum, a head connected to the drive mechanism, at least one grinding plug having a working surface mounted in the head, and at least one channel extending from a position adjacent the working surface into the plenum.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 60/785,787, entitled “Device And MethodFor Extraction Of Dust From A Grinder,” filed on Mar. 24, 2006, which isherein incorporated by reference in its entirety.

BACKGROUND OF INVENTION

This invention relates to a machine and consumables for grindingsurfaces, such as those formed of concrete, and particularly to animproved method for the collection of dust and other loose materialgenerated as part of the grinding process.

SUMMARY OF INVENTION

A common problem that arises in grinding applications is dust or finesleft on the surface that is being ground. Conventional systems, eventhose with relatively efficient dust extraction, leave a large quantityof dust and other material on the ground or other surface being treated.This becomes a problem in four ways.

First, as a grinding process is being carried out, the grinding surfacespass over the loose material, effectively grinding it as much as thesurface being treated. This shortens the life of the grinding surfaceitself, as well as increasing the overall time to complete a particularjob.

Second, the working surfaces of grinders are often cooled with water,producing a dust-water mixture called slurry. Cleaning up the slurryadds time to a grinding operation.

Third, the dust left on the ground obscures the operator's view of thework surface. It is difficult to achieve a consistent finish if theoperator cannot judge the amount of material being removed.

An additional problem with typical grinding machines is that the highsurface feet-per-minute rate grinding of generates a great deal of heatthrough friction that can decrease the life of the tool.

The invention is directed to methods and arrangements for collectingdust in machines adapted to grind surfaces that address these problems.

In one aspect of the invention, plug for a grinding machine comprises ahole bored in the plug for use as a dust collection port.

In another aspect of the invention, plug for a grinding machinecomprises a plurality of holes bored in the plug for use as dustcollection ports.

In another aspect of the invention, a grinding machine comprises ahousing; a drive mechanism, including a shaft extending through thehousing; a shroud surrounding the shaft and abutting the housing to forma plenum; a head connected to the drive mechanism; at least one grindingplug having a working surface mounted in the head; and at least onechannel extending from proximate the working surface into the plenum.

In another aspect of the invention, a plug-type grinding machinecomprises one or more individual shrouds for each grinding plug.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a cross-sectional view of a grinding apparatus illustratingone embodiment of the invention;

FIG. 2A is a side view of a portion of one embodiment of a grindingapparatus according to the invention;

FIG. 2B is an upper perspective view of the apparatus portion of FIG.2A;

FIG. 2C is a lower perspective view of the apparatus portion of FIG. 2A;

FIG. 3A is an upper perspective view of a grinding plug according to oneaspect of the invention;

FIG. 3B is a lower perspective view of the grinding plug of FIG. 3A;

FIG. 3C is a side view of the grinding plug of FIG. 3A;

FIG. 3D is a top view of the grinding plug of FIG. 3A;

FIG. 3E is cross-section view taken along line 3E-3E;

FIG. 4A is a lower perspective view of a second grinding plug suitablefor use with the invention;

FIG. 4B is an upper perspective view of the grinding plug of FIG. 4A;

FIG. 4C is a side view of the grinding plug of FIG. 4A;

FIG. 4D is a top view of the grinding plug of FIG. 4A;

FIG. 4E is cross-section view taken along line 4E-4E.

FIG. 5A is a bottom view of a one embodiment of a grinding headaccording to the invention;

FIG. 5B is an side view of the head of FIG. 5A;

FIG. 5C is a perspective view of the head of FIG. 5A;

FIG. 5D is a cross-section view taken along line 5D-5D;

FIG. 6A is a bottom view of another embodiment of a grinding headaccording to the invention;

FIG. 6B is a side view of the head of FIG. 6A;

FIG. 6C is a perspective view of the head of FIG. 6A;

FIG. 7A is a bottom view of another embodiment of a grinding headaccording to the invention; and

FIG. 7B is a side view of the head of FIG. 7A.

DETAILED DESCRIPTION

This invention is not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the drawings. The invention iscapable of other embodiments and of being practiced or of being carriedout in various ways. Also, the phraseology and terminology used hereinis for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” “having,” “containing,”“involving,” and variations thereof is meant to encompass the itemslisted thereafter and equivalents thereof, as well as additional items.

Referring to FIG. 1, an exemplar floor grinding machine 1 suitable foruse with the invention includes a frame 100, a housing 200, and a grindassembly 400. Suitable grinding machines for use with the inventioninclude, but are not limited to, the Blastrac® BMG 2500 Plug StyleGrinder. Note that “grinding” is defined herein to encompass alloperations that concern the surfacing of hard materials, such asconcrete, stone, terrazzo, and the like, including the processescommonly known as grinding, sanding, polishing, and buffing.

In this embodiment, the frame 100 is connected to a drive mechanismincluding wheels (not shown) and a handle assembly with controls (alsonot shown), as is conventional in the art. A dust collection system (notshown), including a dust collection bin or bag, may be mounted in or onthe housing, or may be separate from the floor grinding machine 1.

In the exemplar embodiment, the frame 100 is connected to the housing200 that supports a motor (not shown) for driving the grind assembly 400via shaft 150. The housing 200, constructed of sheet steel or otherdurable material, includes a top portion 202 as well as peripheral wallportions 204 that extend to the floor or other surface to be ground. Thewall portions may include seals 206 where they meet the surface to beground. The seals, when used, may be rubber or plastic gaskets, nylonbristles, metal shrouds, or any other suitable material or structure, aswould be understood by one of skill in the art.

The shaft 150 projects through the housing 200 and drives one or moreheads 240 in a rotating fashion. In some embodiments, a couplingmechanism 270, such as a Morflex® coupler, may be positioned between theshaft 150 and the one or more heads 240. In one embodiment, the grindingmachine 1 includes two heads 240.

In this exemplar embodiment, each head 240 includes at least one bore245 for receiving a wear plug 300. In some embodiments, the bores 245are tapered, so that the wear plugs 300 may be held in place by afriction fit, aided by the weight of the machine. In one embodiment,each head 240 includes three bores 245 for receiving three wear plugs300.

The wear plugs 300 of this embodiment may be made of any appropriatematerials or materials. One suitable plug is the Blastrac® X TypeDiamond Plug. This plug has an X-shaped extension with a course gritdiamond coating. A Blastrac® X Type Diamond Plug modified for use withone embodiment of the invention is illustrated on FIGS. 3A-3E. Anothersuitable plug would be the Blastrac® 30-40 Grit Diamond Plug, shown, asmodified for use with one embodiment of the invention, in FIGS. 4A-4E.It should be understood that the abrasive used in conjunction with thisinvention also may be formed of or comprise any appropriate material ormaterials other than diamond, and that it may be of any suitable grit.

It should be understood that other wear plugs may be suitable for usewith the invention, as would other types of consumables, including discsor wheels, as would be understood by one of skill in the art.

In the exemplar embodiment, the wear plugs 300 are generally cylindricaland are tapered along at least part of their length, so as to facilitatethe friction fit into bores 245. In other embodiments, the wear plugs300 may be shapes other than cylinders and may or may not be tapered.Other methods of securing the wear plugs 300 into the bores 245 may alsobe used, including threads, clips, pins, bolts, or any other appropriatemethod.

In some embodiments, the wear plugs 300 are attached to the floorgrinding machine 1 by other means, such as by surface mounting andfixation to the head 240 by means of the bolt or other threaded element,or otherwise. The method of connecting the wear plugs to the machine isnot material to the invention.

The wear plugs 300 include a working surface 305, commonly coated with athickness of diamond grit or another abrasive, and one or more channels310. By “working surface” it is meant the portion of the plug thatperforms the grinding operation. In the case of the Blastrac® X TypeDiamond Plug, for example, the working surface would include the face ofthe “X,” indicated by reference numeral 305 in FIGS. 3A-3E. In this andother embodiments, the working surface 305 need not be flat, and mayinstead be convex, concave, or undulating. In some embodiments, theworking surface 305 may have rounded or chamfered edges.

In one embodiment of the invention, the wear plugs 300 include onechannel 310 in the center of the wear plug 300, along its axis. In otherembodiments, there may be, in addition to or instead of a centerchannel, a plurality of channels 310 spaced around the axis of the wearplug 300, either regularly or irregularly.

In the illustrated embodiment, the channels 310 are cylindrical boresthat are approximately ⅜ of an inch in diameter, although othercross-sectional shapes and sizes could be appropriate. Other embodimentsmay employ a larger number of channels of the same, a smaller, or alarger cross-sectional area. In some cases, channels 310 may be of oneor more different diameters.

Where the channels 310 are spaced about the axis, they may run in adirection parallel to the axis of the plug, or some or all may taper inthe direction of, or away from, the axis.

The channels 310 may be arranged such that they all exit the wear plugs300 and the same radial distance from the axis, or, in otherembodiments, the channels 310 may exit the wear plugs 300 at differentradial positions relative to the axis of the wear plug 300. In someembodiments, the channels 310 may exit the plug through the workingsurface 300; in others, they may exit the plug a position proximate to,but not on, the working surface 300.

In the illustrative embodiment, the wear plug 300 also includes a recess320 in the end opposite the working surface 305. The recess 320 may besized and positioned such that each channel 310 opens into recess 320,forming a small plenum, rather than extending to the top of the plug.

In some embodiments, the inventive system includes individual plugshrouds 330 enclosing the portion of each wear plug 300 that protrudesbelow the head 240. The plug shrouds 330 may be made of a flexiblematerial, such as urethane, and may be held in place by friction and/orby a taper on the wear plugs 300. In some embodiments, the plug shrouds330 are sized to have the same axial length as the portion of the wearplug 300 extending below the head 240. As the wear plugs 300 are worn,the plug shrouds 330 also wear, so that shrouds 330 always extend to theworking surface.

In some embodiments, the plug shrouds 330 may include one or morereliefs (not shown) formed on the inside (i.e., the side in contact withthe wear plug 330) to facilitate the flow of air and/or reduce clogging.

On the upper surface of the head 240 of this embodiment there areprojecting tubular cuffs 250 that are positioned to correspond to thelocation of each wear plug 300. In the illustrative embodiment, thecuffs 250 are terminated in a plane such that the radial outermostportion extends further above the top side of the head 240 than theradial innermost portion. The cuffs 250 each receive a hose 260 made ofan abrasive resistant material. The hoses 260 may be sized for afriction fit over the cuffs 250 and/or may be secured with a clamp or byother means.

The other end of each hose 260 is connected to an inverted shroud 210.The inverted shroud 210 is bowl-shaped and surrounds the shaft 150. Thebottom of the shroud 210 is connected to the shaft 150, directly orindirectly, such that it rotates with the shaft 150. The shroud 210 isflexible and is also constructed of an abrasive resistant material. Thelip 215 of the shroud rests against, but is not connected to, the lowersurface of the top 202 of the housing 200.

Extending through the top 202 of the housing 200 is at least one dustevacuation port 280. The port 280 is positioned such that itcommunicates with the plenum formed by the shroud 210 and the top of thehousing 202. The port 280 may be perpendicular to the top of the housingor, as in the illustrative embodiment, arranged with its axis at anangle relative to the top 202 of the housing 200.

An evacuation hose (not shown) connects the port 280 to a dust collector(also not shown).

In operation, the dust collector draws air and entrained dust and finesthrough the channel(s) 310 in each plug, through the recess 320 in eachplug, through the cuffs 250 on the head 240, through each hose 260, andinto the plenum formed by the shroud 210 and the top 202 of the housing200. The air, dust, and fines are then drawn through the port 280 andinto the dust collector.

There are at least four benefits of the inventive system of thisinvention. First, dust is removed much more effectively than previousmethods. Second, with more effective dust removal, the grinding toolitself is able to operate more efficiently. Third, the focused flow ofair through the plugs cools the wear plugs 300, including any diamond orother material forming the working surface 305, and prolongs the life ofthe plug. Fourth, the material is removed more efficiently from thesurface being treated, allowing the operator a better view of theprogress being made.

The holes in the grinding tooling, in effect, become high velocity portsin close proximity to the development of dust. The ports travel with theplug, immediately capturing airborne dust as well as dust falling backto the surface. As a result, only a minimal amount of dust falls to thesurface between plugs, allowing each successive plug can moreefficiently engage the work surface. The system also allows air to flowthrough the tool, dissipating heat and avoiding clean-up associated withwater-cooling of the wear plugs or working surface.

Another embodiment of the invention is illustrated in FIGS. 5A-D. Inthis arrangement, a head 500 carries three wear solid wear plugs 510,which may be mounted by any suitable method. Optional shrouds 520 arepositioned about the solid wear plug 510. One or more local dustevacuation ports 530 extend through the circular head 500 andcommunicate with a gap between the solid wear plugs 510 and the shrouds520. This embodiment provides localized high velocity ports that travelwith each solid wear plug 510, without the need for channels extendingthough the plugs themselves.

FIGS. 6A-C depict another embodiment of the invention. In thisarrangement, a head 600 carries three solid wear plugs 610, mounted, asabove, in any appropriate manner. Positioned behind each wear plug 610,relative to the direction of travel of the rotating head 600, areelongated evacuation ports 630. The elongated evacuation ports 630extend through the head 600 and to the surface being treated. Theelongated evacuation ports 630, which may be made of any appropriaterigid or semi-rigid material and have a cross-section that isrectangular or any other suitable shape, wear as the plugs 610 wear andprovide localized high-velocity dust collection.

FIGS. 7A-B show a head 700 that includes a plurality of wear plugs 710.Positioned behind each wear plug 710, relative to the direction oftravel of the rotating head 700, are elongated agitators 720. Theagitators, which may be made of bristles, urethane, neoprene, or anyother appropriate rigid or semi-rigid material, operate to stir up dustor other debris from the surface of being treated to allow it to beentrained in the flow of air to a dust collection system. Elongatedagitators 720 may be used in a system with conventional dust collection,or in conjunction with one or more of the localized, high velocitysystems described above.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe invention. Accordingly, the foregoing description and drawings areby way of example only.

1. A machine for treating surfaces, comprising: at least one grinding plug having a working surface; and a channel formed in the plug for the collection of loose material generated by the grinding process.
 2. The machine for treating surfaces of claim 1, wherein at least a portion of the channel is located on an axis of the grinding plug.
 3. The machine for treating surfaces of claim 1, further comprising a second channel and wherein the channels extend through the working surface at a uniform radial distance from an axis of the plug.
 4. The machine for treating surfaces of claim 1, wherein the grinding plug comprises a diamond abrasive.
 5. The machine for treating surfaces of claim 1, wherein the outer surface of the grinding plug tapers from the end with the working surface to the end opposite the working surface.
 6. The machine for treating surfaces of claim 1, wherein the working surface is at least partially convex.
 7. The machine for treating surfaces of claim 1, further comprising a plenum formed in the end of the plug opposite the working surface.
 8. The machine for treating surfaces of claim 1, further comprising a shroud surrounding and adjacent to the grinding plug.
 9. A machine for treating surfaces, comprising: a housing; a drive mechanism, including a shaft extending through the housing; a shroud connected to the shaft and abutting the housing to form a plenum; a head connected to the shaft; at least one grinding plug having a working surface mounted in the head; and a channel extending from a location adjacent the working surface into the plenum.
 10. The machine for treating surfaces of claim 9, wherein at least a portion of the channel is located on an axis of the grinding plug.
 11. The machine for treating surfaces of claim 9, further comprising a second channel extending from the working surface into the plenum and wherein the channels extend through the working surface at a uniform radial distance from an axis of the plug.
 12. The machine for treating surfaces of claim 9, wherein the grinding plug comprises a diamond abrasive.
 13. The machine for treating surfaces of claim 9, wherein the outer surface of the grinding plug tapers from the end with the working surface to the end opposite the working surface.
 14. The machine for treating surfaces of claim 9, wherein the working surface is at least partially convex. 15 The machine for treating surfaces of claim 9, further comprising a plenum formed in the end of the plug opposite the working surface.
 16. The machine for treating surfaces of claim 9, further comprising a shroud surrounding and adjacent to the grinding plug.
 17. A grinding plug comprising: a working surface; and a channel extending through to the working surface.
 18. The grinding plug claim 17, wherein at least a portion of the channel is located on an axis of the grinding plug.
 19. The grinding plug of claim 17, further comprising a second channel and wherein the channels extend through the working surface at a uniform radial distance from an axis of the plug.
 20. The grinding plug of claim 17, wherein the working surface is formed of a diamond abrasive.
 21. The grinding plug of claim 17, wherein the outer surface of the grinding plug tapers from the end with the working surface to the end opposite the working surface.
 22. The grinding plug of claim 17, wherein the working surface is at least partially convex. 